The invention relates to cathode-ray tube comprising a system for generating an electron beam and a deflection system for deflecting the electron beam, which includes a picture and a line deflection system, the line deflection system having two line deflection coils arranged in parallel by means of a first and a second coupling, the first and second couplings being coupled to a first and a second energizing terminal for the supply of a line deflection voltage.
Cathode-ray tubes of this type can be used in black-white, colour and projection television tubes, in data reproducing equipment and in other equipment in which a cathode-ray tube is used.
Such a cathode-ray tube is disclosed in the U.S. Pat. No. 4,431,940.
One feature which is important for the quality of the picture display is the extent to which the what is commonly referred to as "ringing" phenomenon occurs. This phenomenon occurs immediately after the line retrace and can show as a striped pattern at that edge of the picture screen where the line scan of the picture screen starts. A possible solution of this problem can be achieved by allowing the picture screen to be overscanned. This solution does not reduce the phenomenon, but the consequences of this phenomenon are not visible on the screen. This solution has however the disadvantage that the speed at which the information is displayed on the picture screen must be reduced, as the electron beam does not impinge on the visible portion of the picture screen during a part of the time. It is also necessary for the electron beam to be deflected through a wider angle, for which more energy must be applied to the deflection coil system. An alternative solution of this problem is to reduce capacitive couplings between the line deflection coils and the environment to the best possible extent. Ringing can also be caused by capacitive coupling between the line deflection coils of the line deflection system and the environment. The line deflection system and the environment form a LC circuit which is caused to resonate in response to potential differences which suddenly occur during the line retrace. Inherent to such a solution is however that the line deflection coils and/or the environment must be modified therefor. It is therefore an object of the invention to reduce "ringing.infin. for a cathode-ray tube of the type defined in the opening paragraph without a modification of the design of the line deflection system and/or the environment being required.